This set of still images from the NOAA/POES satellite are derived from measurements by particle detectors in low Earth orbit. The data are sampled along the orbit track and then interpolated in time and position for the rest of the polar region. This interpolation is responsible for the curved block-shaped artifacts in the images. Note: POES data showing particle fluxes at or near their lowest levels. Animator: Tom Bridgman (GST). Scientist: Xiaohua Fang (University of Michigan), David Evans (NOAA/SEC). Writer: William Steigerwald (NASA/GSFC).